Example embodiments relate to a semiconductor device, and more particularly to a memory device and a memory system having the memory device.
In general memory systems, a memory controller controls an operation of a memory device using fixed parameters.
However, a memory device may include a plurality of memory blocks each may have different physical characteristics, and only some of the memory blocks may need to be refreshed.
Therefore, if a memory controller controls an operation of a memory device using fixed parameters, performance of the memory system may be degraded.